Temperature control system



April) 15, 1941. c. w. NEssELl. 2,238433 TEMPERATURE CONTROL SYSTEM Filed D60. 21, 1936 nsf-HW Nu (1% 2,- Hyg-25,6 m n .2 mk@ Inventor Clarence Wjlessell Bg I ,el @JM #0141163 I Patented Apr. 15, 1941 TEMPERATURE CONTROL SYSTEM` Clarence W. Nessell, Dayton, Ohio, Aassignor to Minneapolis-Honeywell' Regulator Company, Minneapolis, Minn., a corporation of Delaware Application December 21, 193s, serial Ne. 116,886

13 Claims.

My invention relates to a temperature control system and more particularly to that type known as a dual control system.

In certain types of heating systems where a number of different rooms or other compartments are to be heated, it is customary to provide a temperature responsive device in each of the rooms or compartments, which temperature device in turn controls a temperature changing device in the room. In such systems, it has been proposed to simultaneously vary the temperature .maintained in all of the rooms by a simultaneous adjustment of .all of the temperature responsive devices. A particular use for such an arrangement is where it is desired to lower the temperature at night. In such cases, some master control located at a convenient control point, such as a basement, is employed to lower the control point of all of the temperature responsive devices at night and in the morning to again raise the control point of these devices. In the type of control system just mentioned,

it is desirable to have some means in the individual rooms for individually adjusting the thermostatic device independently of the master control. Thus where the master control has called for the night temperature to be maintained, an occupant of one of the rooms may quite likely desire to have the day temperature maintained for at least a short time. The present invention is concerned with a system of the type described wherein an .electrically operated means is associated with each of the temperature responsive devices, which electrically operated means is capable of individually adjusting the temperature responsive device with which it is associated.

An object of the present invention is accordingly to provide a temperature control system employing a plurality of temperature changing means, a control device for eachrteniperature changing means, means for adjusting each o! the control devices, master control means for operating all of the adjusting means in unison to change .the temperature maintained by each temperature changing device, and electrically operated means associated with each adjusting means for operating any one of the adjusting means independently of lthe master controller.

' A further object of the invention is to provide a temperature control system of the type of the previous object wherein all of the adjusting means are restored to the control of the master control means upon operation of the latter.

A further object of the present invention is to provide a condition control system employing a number of condition changing devices, each of -which is regulated by a condition responsive control means, in which means including a relay isemployed with each condition control means for changing the control point thereof, a master control device is employed for simultaneously energizing and deenergizing all of the relays, and

switching means is associated with each relay for energizing and deenergizing the same independnumeral I0. Located within the conditioning chamber is aA steam heating coil Il. This coil is supplied with steam from a supply pipe I3 leading to any suitable source of steam (not shown) and the iiow of steam from supply pipe I3 to coil II is controlled by an electrically operated valve I2. Leading into the conditioning chamber I0 are a fresh air duct I4 and a return air duct I5. Both of these ducts areprovided with damper means to regulate the proportional amounts of fresh air and return air entering the' conditioning chamber; A fan I6 is employed to circulate the air through lthe various rooms. This fan is driven by a motor I1 of any suitable form. The air is forced by the fan I6 through the supply duct I8 which is provided with outlets I9 opening into the individual rooms, the floors of which are indicated by the numerals I, 2 and 3. Located inA each outlet I9 is a damper 20 which serves to control the amount of heated "air entering the room. It will be readily seen g that the outlet duct constitutes a temperature changing device for the room in which it enters and thevdamper 20 a regulating means for this temperature changing device.

Included in the control equipment for each room is 'a motor assembly, a. thermostat and a relay. lThe motor assemblies are 'indicated by the 'reference numerals 2|, 22 and 23. The thermostats for these motor assemblies are indicated .by the reference numerals 24, 25`and 26, respectively. lhe relays associated with the previously mentioned equipment are referred to by the reference numerals 2l, 28 and 29, respectively.

Also included with the control equipment for each room are a day push button and a night push button. The day push buttons are respectively indicated by the reference numerals 39, 3| and 32 and the night push buttons by the reference numerals 33, 34 and Also included in the control equipment in general is a time switch 68 and three relays @L62 and While various equipment has been referred to as assoI ciated with each room, it is to be understood that at least the relays 2li, Z8 and Z9 can be located in the basement or some other point where they are out of the way. They have been shown in the drawing as located in the various rooms merely for aiding in the understanding of the operation oi the system.

A step-down transformer is employed to supply power for the operation of the control system. This transformer comprises a line voltage primary 31 and a low voltage secondary The primary si is connected to line wires 39 leading to a suitable source of power (not shown). The secondary 538 is connected to conductors lill and All which extend upwardly adjacent each of the rooms and serve to feed power for the operation of the various motor assemblies. 23 is provided with terminals i2 and i3 which are connected to line wires il and 4t, respectively.

The thermostat and motor assemblies act to variably position the damper 2t in accordance with the temperature in the individual rooms so as to maintain this temperature substantially constant. The control system is provided with Each of the motor assemblies 2l, 22 and Cil means for compensating the same to change the While the operation ofthe system will be briefly described, reference is made to the above application for a more thorough understanding of this portion of the apparatus.

Located within the motor assembly 2| and' serving tomove the damper 28 is a motor 45. This motor may be of any suitable reversible type and is shown for convenience as a motor employing two rotors 46 and 41 and associated eld windings 48 and 49. When field winding 48 is energized, the motor is rotated in one direction and when field winding 49 is energized, the motor is rotated in the opposite direction. The motor drives, through any suitable reduction gear train a shaft 5|. The shaft 5I is connected through a rack and pinion 52 to the damper 20. 4

Also secured to shaft 5| is a switch actuating arm 53, preferably of insulating ,material. This arm 53 is adapted to cooperatewith a switch consisting of switch blades 54 and 55, which blades are biased into contact making engageis connected to conductor 4| which, as. previ' ously stated, leads to one side of the secondary of the transformer while terminal 51 is connected through a conductor 58 to one terminal of the electrically operated valve I2. The other amarres terminal of the electrically operated valve is connected through conductor 59 to the conductor l@ which, as previously stated, leads to the other side of the secondary 98. It will readily be seen that the valve i12 is energized whenever the switch blades 5t and 55 are closed. As previously indicated, these blades are closed except when the damper 2li is in its completely closed position. Each of the motor assemblies 222 and which are identical in structure to assembly 2l, are similarly provided with the switching arrangement just described and the terminals 56 andi'l of these assemblies are similarly connected so as to control the cnergization of the valve l2, in parallel with the switch of assembly 2l. Ilhus, so long as the damper in any room is at least partly open, valve l2 will be energized and held in its open position to supply steam to coil ll. Upon all of the dampers, however, being moved to closed position` as a result of the absence of a call for heat in any of the rooms, valve l2 is closed to shut oli the supply of steam to the coil il.

A relay coil 65 is connected across the power supply by being connectedI to terminals l2 and 43. Associated with the relay coil G5 is an armature t6 which -is in turn, connected to a relay arm 61. The relay arm 61 is adapted to be moved by armature 66 into engagement with either of two contacts 68 and- 69. The switch blade 4|51 is electrically connected through conductor 18 with one supply terminal 42 and the junction of windings 48 and 49 is connected through conductor 1I with the other supply terminal 43. It will thus be seen that when relay coil 65 is so energized as to effect engagement of switch arm 61 with contact 68, field winding 48 will be energized while when the relay winding 65 is so energized that the switch blade is moved into engagement with contact 69, field winding 49 is energized. The motor is so'designed and so connected to shaft 5I that when field winding 48 is energized the motor I rotates in a direction to move the dampers towards closed position and when field winding 449 is energized the motor rotates shaft 5| in a direction to effect opening of damper 20.

The thermostat 24 comprises a resistance 12 and a contact arm 13 slidable thereover. The resistance 12 and contact arm 13 constitute the control potentiometer for the motor assembly. Operatively connected to the contact arm 13 is a bimetallic' element 14 or any other suitable temperature responsive device capable of imparting movements to an object upon changes in temperature. The thermostat 24 is provided with terminals 15, 16 and 11. The opposite ends of resistance 12 are connected to terminals 15 and 11 while the contact arm 13 is connected through bimetallic element 14 to the terminal 18. Located within the motor assembly are protective resistances 18 and 19. 'I'he motor assembly is provided with thermostat terminals The protective resistances 18 and 19 are connected between the opposite ends of relay coil 65 and terminals 80 and 82. Terminal 8| is connected to the mid point of relay coil 65. Contacts 15, 16 and 'I1 of the thermostat 24 are' connected to the thermostatic contacts 80, 8| and 82, respectively, of the motor assembly. It will be readily seen that the control potentiometer is connected to the relay coil 65 in parallel with the source of power in such a manner that the position of the contact arm 'I3 controls the relative energization of the two halves of relay winding 465.

Also located within the motor assembly 2| is a rebalancing potentiometer Vcomprising the resistance 85 and a contact arm 86 which is secured to and rotatable with shaft 5I. The opposite ends of resistance 85 are connected to the relay coil 65, through the resistances 18 and 19. The contact arm 86 is connected through a desensitizing resistance 81 to conductor 88 which, in turn, is connected to the mid point of relay coil 65. It will thus be seen that the rebalancing potentiometer constituted by resistance 85 and contact arm 86 is connected in parallel with the control potentiometer to the relay 65. It will furtherV be noted that any movement of the contact arm of either potentiometer relative to its associated resistance affects the relative energization` ofv the two halves of relay coil 65 and if the energization of d the relay coil is previously balanced, results this energization being unbalanced.

The loimetallic element 14 is so arranged that any increase in temperature causes the arm 73 to be deflected to the right as indicated in the vapplied. to the right-hand side.being increased, 1 lthus unbalancing the energization of the relay coil and causing armature 66 to move towards the right. The movement of armature 66 to the right causes switch arm 6'! to engage with, contact and thus result in the energization. of eld winding 49 of motor d5. As previously explained,

the energization of this field winding causes the shaft 5i to rotate in a direction to eiect movement of the damper towards open position.

This movement oi shaft 5i is in a clockwise direction.

inasmuch as the contact arm 86 of the rebalancing potentiometer is rigidly secured to shaft 5 the movement of shaft 5I in a clockwise direction results in the movement of contact arm tt to the right. The movement of contact arm 85 to the right tends to increase the energization of the left-hand side of relay coil and decrease the energization of the right-hand side of relay con 55. movement of contact arm 86 is opposite to that of the movement of contact arm i3 of the control potentiometer which initiated the movement of the motor so that if this movement of contact arm is continued sufficiently long, the energization of relay 65 will again be rebalanced. The movement of shaft 5l will continue until relay 65 is again so rebalanced at which time contact arm 61 will be moved out of engagement with contact 6 and the motor will be deenergized. f By reason of the fact that desensitizing resistance S1 is inserted in the connection between the contact arm 86 of the rebalancing potentiometer and the mid point of relay coil 65 and such a resistance is not included in the connection between the contact arm 73 and the mid point of the relay coil, the action of the rebalancing potentiometer will be less sensitive.v As a result, for any movement of contact arm73 of the control potentiometer, it is necessary. for there to be a It will be noted that the effect of this much greater movement ofthe contact arm of the rebalancing potentiometer before the system is rebalanced. In other words, the damper 26 is moved from full open to f ull closed position as a y the control and rebalancing potentiometers. Terminal 94 of the assembly 2| is connected through a desensitizing resistance 91 with the conduc-` tor 88 leading to the mid point of relay coil 65. Terminals 93, 94 and 95 are adapted to be connected to the relay 21 and when so connected, the relay is operative when deenergized to connect terminals 93 and 94 and when energized to connect terminals 94 and 95. Since terminal 94 is connected to the center of the relay coil 65, it will be obvious that the'action of the relay 21 is to connect the mid point of the rel-ay coil 65 with either tap 9i or 92.

When the mid point of coil 65 is connected tov tap 9|, because of the relay being deenergized, a further potentiometer is in effect, introduced into the system, which potentiometer is tapped at a point considerably to the right of its center. The

result is that in order for the system to be balanced, it is necessary for the contact arm "i3 of the control potentiometer to assume a position considerably to the left of mid position, which position corresponds to a lower temperature. The position assumed will be one inv which the supply of heat furnished to the room by reason of the position of damper 2G will be just sumcient to maintain the room at a temperature corresponding to one to the left of the center of resistance '52.

Upon energization of relay 2l with the resultant connection of terminals 94 and 95, the center of relay coil 65 is connected to the-tap Q2 of resistance 9B. As soon as this takes place, the system is immediately unbalanced by reason of the fact that the center wire is nolonger connected to a point to the right of the mid point of resistance but is connected to a point on the left side of the center of resistance @il In order for the system to again be rebalanced, it is necessary for the contact arm'lS to assume a position considerably to the right of the center of resistance l2. new position of contact arm i3, an increased amount of heat will be supplied to the room which increased amount will be sulcient to maintain the temperature at a higher deired value. When the center of the relay coil 65 is connected to tap 9i, which will be during night operation, the thermostat will control about a range to the left of the mid point of resistance 'F2 while when the centerpoint is connected to tap 92 the thermostat will control about a range to the right of the center of resistance l2. Due to the presence of desensitizing resistance 81, the thermostat, even though controlling over limited temperature ranges, can cause movement of the damper over substantially its entire range of movement. By reason of the presence of the desensitizing resistance 9T in the connection between the center of relay coil 65 and the taps 9i or 92,' the eiect of the compensating resistance is reduced. This is necessary in order to prevent the shift of the c ntrol point of thermostat 2H from being too great.

For a more complete understanding of this method of shifting the temperature maintained, reference is made to the above mentioned application of John. E. Haines.

The relay 2l comprises a relay coil Hdl which is designed to actuate a sereis oi relay arms db2, Hdd, Hild and llti. Relay arms H22 and HHB@ are Aadapted to engage with contacts Het and Hill, respectively, when in the deenergized position of the relay. Relay arms M22, Hdd and Hll are adapted to engage with contacts H22, H29 and HH@ upon. energization of the relay coil Mil. it is to be understood that the various relay arms are biased to theirdeenergized positions so that upon deenergization of the relay, these arms move immediately to their deenergized position which is the position in which they are shown in the drawing. Relay coil Hdl is connected at one end to terminal HHH and at the other end is connected to terminals HH2 and HHS, which terminals are electrically connected together. The relay arms 22, HHlB, lill and H25 are connected to terminals lHEl, respectively. Contacts H26, Hlil, it@ and H29 are connected to terminals H22, HHil, H2@ and i2i. rihe contact HH@ is connected to terminal HHH.

While the internal structure of only motor assembly 2H, thermostat and relay 2l have been described, it is to be understood that the corresponding devices in the other control units are identical. These devices have accordingly not been shown in detail in the drawing and have been shown merely in outline. The various terminals ofthese other control devices have the same reference numerals applied to them as were applied in connection with the description of devices 2H, 2d and 271.

rEhe relay iii comprises a relay coil H25 which is designed to cooperate with relay arms H2@ and H2'H. These relay arms are adapted upon energization of the relay to be moved into engagement with contacts and H29, respectively. The relay arms are biased out of engagement with their respective contacts.

Relay t2 comprises a relay coil 832 and relay Hlll and being moved into engagement with contact H65 upon energizationof the relay coil Hliii. Contact arm Hdl is of the overlapping type so that upon energization of the relay coil it vengages contact Hlb before it separates from contact Hlll. Relay arm 8d2 is adapted to engage a contact Het when the relay is deenergized while relay arm H43 is adapted to engage a contact Ml upon energization of the relay.

Operation The various elements are all shown in the position they occupy during the night. viously explained, the normal condition is that the relays 2l, 28 and 29 are energized during the day and deenergized at night, the deenergization being eiected by the opening of time switch tu. During the day, relay @il is deenerenseres t@ through .conductor titl, conductor Het, relay coil H25, conductor HH, terminal HH@ of relay 2li, relay arm Hlli, contact Htl, terminal HHl o relay 2l, conductor H52, terminal HHli of relay 2&3 to terminal HH@ of the same relay, conductor H53, terminal HHii of relay 29 to terminals HHS and HHll of the same relay, and through conductor H5@ to the other terminal oi secondary lThe circuit just traced includes the paths from terminals HH@ to HH@ of the several relays. lt is to be understood that these terminals are connected together when the relays are deenergized, inthe same manner as terminals HHHi toI HH@ of relay 2li are connected by the engagement of contactv Hill and relay arm HllS when relay HHlH is de energized. Similarly, whenever two terminals of relay 2l are shown as connected by reason of either an energized or deenergized position of relay coil HtH, the corresponding terminals of the other relays are also connected if these relays are similarly energized.

li'he energizing circuit traced in the preceding paragraph results in the initial energization of relay coil H25. rThis causes relay arms H2@ and H21! to be moved into engagement with contacts H25 and Q29, respectively, as shown in the drawing. The moving of the relay arm. H2@ into engagement with contact H22 results in the following holding circuit for relay coil H25 being established: from. secondary 22 through conductor dil, conductor Hell, relay coil H25, contact H26, relay arm H25, conductor Het', contact Hlll, relay arm HiH and conductors lill and 6H to the other terminal of secondary Sii. It will be noted that the new circuit is independent of relays 2li, 2t and 2i] so that if any of these relays are sub# sequently energized, relay coil H 25 will still remain energized. i

As previously stated, the various elements are shown in the position which they occupy at night. In this position, the various relays 2l, 28

' and 29 are deenergized so that in each case the terminals 93 and 96 of the motor assembly are connected through the engagement of relay arm HQE with contact HHlt. As previously explained, when these terminals are so connected, a lower temperature is maintained in the room. If it is desired under these conditions to restore a higher temperature to any one of the rooms, the day push button for that particular room is actuated. Let it be assumed that it is desired to restore day temperature in the room located between the iloors designated by the reference numerals i and 2. The actuationof day push button Sil causes the following circuit to be established to relay coil Hili: from one terminal of secondary 3B through conductors it@ and H55, day push button switch it, conductors M52 and M53, relay coil HllH, terminal HH2, conductor H55, contact E29, relay arm H2ll and conductors Het and lll, to the other terminal of secondary Sil.

'The energization of 4relay coil HtlH as a result of the establishment of the previously traced circuit causes contact arms lllZ, Htil and H05 to move into engagement with contacts H02, H29 and HHHll, respectively. The moving into engagement of relay arm H25 with contact HH@ establishes the following holding circuit to relay'coil lill from one terminal of secondaryl 38 through conductors HSS and BSH, the night push button switch 33, conductor H58, terminal M8, relay arm :25,

minal ||2, conductor |65, contact |29, relay arm |21 and conductors |66- and 4| to the 'other terminal of secondary 38. It will b e noted that the holding circuit for relay coil just traced is independent of the push button switch 30 and is dependent upon the push button 33 remaining in its normally closed position. y

The moving into engagement of relay arm |02 with contact |08 results in terminal 94 of the motor assembly being connected to terminal 95 which, as previously explained, causes a higher day temperature to bezmaintained. While the movement of relay arm |03 out of engagement with contact |01 results in the interruption of the previously established energizing circuit for relay coil of relay 6|, this relay coil is not deenergized because of the prior establishment of the previously traced holding circuit for the same.

' The relay 21 will thus continue to remain energized, maintaining a higher temperature in the one room independently of that maintained in the others 'and independently of time switch 60. Whenever it is desired to deenergize the relay 2-1 and restore the room in question to night l of the intervening separation of relay arm |05 from contact H0. Y

As soon as the time switch 60 closes its contacts, which will take place at a desired time in the morning, the following circuit is established to relay coil |32 of relay 62: from one side of the secondary 38 through conductors 40 and |12, time switch 60, conductors |13,- |14, |15, |16, and |18, relay coil |32, conductor |19, contact |46, contact arm |42 and conductors |80, |.51 and 4| to the other side of secondary 38. Y

The energization of relay coil |32 as the result of the establishment of this circuit causes vrelay arms |33, |34 and |35 to move into engagernent with contacts |36, |31 and |38, respecarm |33 with contact |36 will result in the establishment of the following energizing circuit for relay coil |0 from one terminal of secondary 38 through conductors 40 and |12, time switch 60, conductors |13, |14, |15, and |16, relay arm |33, contact |36, conductor |82, terminal conductor |63, relay coil |0|, terminal ||2, conductor |65, contact |29, relay arm |21 and conductors |66 and 4| to the other terminal of secondary 38. Y

Contact |31 is connected'to terminal Vof relay 28 in the same manner as contact |36 is connected to terminal of relay 21. Similarly, contact |38 is lconnected to terminal of relay 29. Contacts ||2 and ||3 and all of the relays 21, 28 and 29 are connected in series and to conductor |65. It will thus be readily seen that engagement of relay arms |34 and 35 with lay arm |21 of relay 6|. Inasmuch as it is assured that `relay 6| is in its energized condition byreason of the establishment of its holding circuit, there1is an assurance that all of the relays 21, 28 and 29 will be energized uponl closure of the time switch.

It will be noted that the above described energizing circuits for the relay coils of the relays 21, 28 and 29 areindependent of the various push buttons in the rooms. While it is highly desirable to insure that these relays are initially energized independently of these push buttons, it is also desirable that the control of the relays be transferred back to the bush buttons Aso that the temperature in the various rooms can be regulated independently of the time switch if desired.

Thus, as soon as the relays 21, 28 and 29 are pulled in, an energizing circuit is established for relay coil |40 as follows: from one terminal of secondary 38 through conductors 40 and |12, time switch 80, conductor |13, relay coil |40, conductor |84, terminal |.2| of relay 21, contact |09, relay arm |04, terminal ||1 of relay 21, conductor |86,

terminals I2| and ||1 of relay-28, conductor |88, terminals I2| and ||1 of relay 29 and conductor |54 to the other terminal of secondary 38.

-The establishment of the previously traced circuit. results in the energization of relay coil |40. The energization of this relay coil causes contact arms |42 and |4| to move out of engagement with contacts |46 and` |44 and alsolcauses contact arms |4'| and |43 to move into engagement` withcontacts 'i 45 and |41, respectively.

The engagement of relay arm |43 with contact |41 'results inthe establishment of the following holding circuit for relay coil |40: from one terminal of secondary 38 through conductors 40 and |12, time switch 60, conductor |113, relay coil |40, contact |41, relay arm |43, conductors |80, |51 and 4| to the other terminal of secondary 38.

The moving of switch arm |42 out of engagement with contact |46 results in the energizing circuit for relay coil |32 being interrupted so Y that this relay is again deenergized. The result contacts |31 and |38 causes relays 28 and 29 to y be energized in the same manner as the engagement of relay arm |33 with contact |36 results inthe energizaton of relay 21. Thus, the energization of relay coil |32 results in the simultaneous energization of relays 21', 28 and 29 through a circuit including the relay arms and contacts of relay 62 and the contact |29 and reof the deenergization of this relay coil is that all of the previously traced energizing circuits Vi'or relays 21, 28 and 29 are interrupted. Mo-

mentarily, however, and before contact arm |4| definitely separates from contact |44, each of these relays 21, 28 and 29 is maintained energized by the holding circuit' through contact arm |05 and contact' ||0 and through contact |29 and contact arm |21, which holding circuit was traced previously in connection with the description of the operation upon actuation of the day push button during the night cycle. As soon as relay arm |4| leaves contact |44, however, the holding circuit just traced is interrupted. Before this holding circuit is interrupted, however, contact arm I4| has engaged contact |45. The result is that a new holding circuit is established for each of the relay' coils 21, 28 and 29. The new holding circuit for relay coil |0| of relay 21 is as follows: from one terminal of secondary 38 through conductors 40, |60 and |6|, night push button 33, conductor |68, terminal H8, relay arm |05, contact H0, conductor |69, relay coil |0|, terminal I2, conductors |65 and |90, contact |45, relay arm |4| and conductors |51 and 4| to the other terminal of secondary 38.

It is believed unnecessary to trace the new holding circuits for each of the other relay coils.` In each case the circuit is from conductor |60 through the night push button of the room to M2 and since all of the terminals eral rooms.

terminal il@ through the relay coil to terminal M2, il@ are connected in series to conductor i655, as previously stated, from terminal M2 to the other terminal of the secondary.

It will be noted that during the previously described operation following the closure of the time switch 60, relay 62 was energized and then deenergized. A function of this relay is to insure that all of the relays 21, 28 and 29 are initially pulled in regardless of their previous condition. As soon as all of these relays have pulled in, as indicatedby the energization of relay 63 whose initial energizing circuit is dependent upon the closure of all the relays 21|, 2t and 29, relay 62 is deenergized restoring the control of the individual relays 21, 28 and 29 to the day and night push buttons in the sev- It is thus assured that all of the relays are automatically placed under control of the time switch when the same closes, regardless of their positions at the time of closure 'of the time switch.

It will be noted that the individual energizing circuits for the relay coils of relays 21, 28 and 29 were broken upon the deene'rgization of relay 62. Moreover, the only holding circuits for these relays are through the respective night push buttons. Consequently, if in any room, it is desired to go to night temperature during the day cycle, all that is necessary is to push the respective night push button. Thus if it is desired to maintain a lower night temperature in the room in which relay 21 is located, actuation of push button 33 will open the, holding circuit for relay 21 resulting in the continued deenergization of the same even after release of the push vbutton because of the fact that this deenergization results in the separation of relay arm |05 and contact H0. The subsequent closure of the night push button upon release thereof does not re-establish the energization of relay coil IUI. If, however, at a later time oi' the day it isl again desired to re-establish the day temperature in the room, all that is necessary to do is to push the day push button 30. The effect of pushing this button will be exactly the same as that previously outlined in connection with the actuation of the same during the night. The only difference will be that the energizing circuit for relay coil |0| established as a result of actuation of the day push button 30 will be from conductor |65 through conductor |90 and contact |45. contact arm I4| and conductor |51 instead of through contact |29, contact arm |21.

and conductor |66. In other words, during the night the energizing circuits for relay coil of the relays 21, 28 and 29 are-dependent upon the closure of relav 6I whereas in the day the energizingj circuits for these relay coils are dependent upon the closure of relay 63.

Since all of the possible energizing and holding circuits for relays 21, 28 and 29 during the day are dependent upon, the energization of relay 63, and the energization of this relay. in turn, depends upon the closure of time switch 60, it will be obvious that the opening of this time switch at the end of the day cycle results in the deenergization of all of the relays. Thus, it is assured that regardless of their position whenl the time switch cycles, all of the'relays 21, 28 and 29 are deenergized, thus resulting inthe various controls being shifted to their night setting.

As soon as the time switch does open at the end of the day cycle and the various relays are y each relay coil for energizing said relay coil up'o'n momentary actuation thereof from a rst pcsl aasafica deenergized, the relay coil i2@ will be again energized through the same energizing circuit as traced in the iirst portion of the operation of the system. This, in turn, will again result in the establishment of the holding circuit for relay coil M5 and the apparatus will be in the condition previously described for the night cycle.

It will be readily seen that by means of my control system, it is possible entirely by electrical means to go from night to day setting and back in any one room regardless of the setting of the master control, which in the illustrative embodiment is the time switch. Moreover, regardless of the settings of the control devices in the various rooms, they are all placed under the control -of the master control at the time that this master control again cycles.

It is to be understood that while a certain type of individual temperature control system for each room has been described, my system in general is applicable to various types of temperature control systems. Thus, instead of the compensated control system shown wherein the dampers are variably positioned, it would be possible to have an on andofi control system with means for compensating the individual thermostats. Moreover, it would be entirely possible to ,employ a day and night thermostat foreach room with the relay switch |02 functioning to transfer the damper motor from the control of the day tothe night thermostat and vice versa. lOf course, it is obvious also that the control system is not limited to an indirect radiation type of heating system but is applicable to any case where there are a number of temperature changing devices with individual regulation of each device.

In general, While I have shown a certain specic embodiment of my invention it is to be understood that this is for purposes of illustration and that my invention is to be limited only by the scope of the appended claims.

I claim as my invention: I

1. In a condition control system, a plurality of condition changing means, an electrically operated regulating device for each of said condition changing means, a single condition responsive control device for each of said regulating devices, circuit connections between each of said control devices and its associated regulating device and eiective to permit said control device to cause said regulating device to maintain the controlled condition at a substantially constant value, means including a two position relay switch for each control device for altering said circuit connections between the control device and the regulatingdevice to cause either of two values of said condition to be maintained, a relay coil associated with each relay switch and effective when energized to move said relay switch from a first position towards which it is biased to a second position, master control means including a time switch for periodically energizing and deenergizing al1 of said relay coils, and means including switching means associated with tion to a second position independently of. said master control means and of the other relay coils.

2. In a condition control system, a plurality of condition changing means, an electrically operated regulating device for each of said con dition changing means, a single condition lr sponsive control device for each of said regu- .lating devices, circuit connections between each of said control devices and its associaited regubiased to a second position, master control means including a time switch for periodically ener.

gizing and deenergizing all of said relay coils, and switching means associated with each relay coil for deenergizing said relay coil upon momentary actuation thereof from a. rst position to a second position independently of said master control means and of the other relay coils.

3. In a condition control system, a plurality of condition changing means, an electrically operl ated regulating device for each of said condition changing means, a single condition responsive control device for eachl of said regulating devices, circuit connections between each of said control devices and its 'associated regulating device and eiiective to permit said'control device -to cause said regulating device to maintain the controlled condition at a substantially constant value, means including a two position relay switch for each control device for altering said circuit connections between the control device and the regulating device to cause either oi two values of said condition to be maintained, a relay coil associated with each relay switch and eiective when energized to move said relay switch from a first position towards which it is biased to a second position, master control means including a time switch for periodically energizing and deenergizing all of said relay coils, and means including switching means` associated with each relay coilior energizing `said relay coil when deenerglzed by said master control means and deenergizing the same when energized by .-said master control means in response to momentary actuation thereof from a rst position to a second position independently of said master control means and of the other relay coils.

4. In a condition control system, a plurality of condition changing means, an electrically operated regulating device for each of said condition changing means, a single condition responsive control device for each of said regulating devices, circuit connections between each of said control devices and its `associated regulating device and effective to permit said control device tocause condition at a substantially constant value, means including a two position relay switch for each control device for altering said circuit connections between the control device and the regulating device to cause either of two values of said condition to be maintained, a relay coil associated with` each relay switch and effectivel sult of theactuation of the switches associated with the individual coils.

5. In a condition control system, a plurality of condition changing means, an electrically operated regulating device for each of said condition changing means, a single condition responsive control device for each of said regulating devices, circuit connections between each of said control devices and its associated regulating device and effective to permit said control device to cause said regulating device to maintain the controlled conditionat a substantially constant value, means including a two position relay switch for each control device for altering said circuit connections between the control device and the regulating device to cause -either of two values of said condition to be maintained, a relay coil associated with each relay switch and eiiective when energized to move said relay switch from a rst'position towards which it is biased to a second position, means including a switch associated with each 'relay coil for deenergizing said relay coil independently of the other relay coils,"and master control means including a time switch operative toperiodically energize and deenergize all of said relay coils independently of controlled condition at a substantially constant.

value, means including a two position relay switch for each control device for altering said circuit connections between the control device and the regulating device to cause either of two ,values of said condition to be maintained, a relay coil associated with each relay switch and effec-- tive when energized to move said relay switch from aiirst position towards which it is biased to a second position, master control means including a time switch for periodically energizing and deenergizing allL of said vrelay coils, and

` means associated with each condition respony said regulating device to maintain the controlled sive control means for actuating the associated relay switch independently of the other relay switches and of the master control means.

7. ln a condition changing system for a plural'ity of zones, conditionchanging means for each zone, condition responsive means in each zone, circuit connections between each condition responsive means and the associated condition changingmeans for varying the condition changing effect of the condition changing means by an amount which is in proportion to the departure of the condition in the respective zone from apredetermined value,'means for altering saidcircuit connections to adjust said predetermined value so that different values of the condition will be maintained within the respective zones depending upon the circuit connections, timing means for periodically and simultaneously altering the circuit connections between the condition responsive means and the associated condition changing means to periodically vary the value ofthe condition being maintained in the various zones for predetermined lengths of time, and manuali means for altering SSB any of the circuit connections whereby the temperature in any selected zone at any time may be changed to the value normally maintained in the zone at a dil'erent time.

8. l'n a condition changing system for a plurality or zones, condition changing means for each zone, condition responsive means in each zone, circuit connections between each condition responsive means and the associated condition changing means for varying the condition changing eiect of the condition changing means by an amount which is in proportion tothe departure of the condition in the respective zone from a predetermined value, means for altering said circuit connections to adjust said predetermined value so 'that diierent values or" the condition will be maintained within the respective zones depending upon the circuit connections, timing means for periodically and simultaneously altering the circuit connections between the condition responsive means and the associated condition changing means to periodically vary the value oi the condition being maintained in the various zones for predetermined lengths of time, manual means for altering any of the circuit connections whereby any oi the condition responsive means may be caused to maintain one said predetermined condition at a time when it would normally loe set to maintain the other predetermined condition, and means for automatically restoring control oi the timing means over all of the condition responsive means at the beginning. of each timing period.

9, ln a system of the class described iorcontrolling the condition of a plurality oi spaces, condition changing means including a condition regulating device ior each of thel various spaces, condition responsive means for each of said spaces, means operated by the condition responsive meansfor varying the position of said regulating device by an amount which is proportional to the departure in the value of the condition from a. normal value, timing means for automatically changing the normal value or" the condition to be maintained in each of the spaces at predetermined times during the day so that the conditions of the spaces will be maintained at diierent values during different portions of the day, and means for causing the condition responsive means in any one space to maintain during one portion of the day the condition at the value that is normally maintained during the other portion of the day, and means for causing all of the condition responsive means to return to normal control at the beginning of each timing period.

l0. ln a condition changing system for a plurality of, zones, condition changing means for each zone, condition responsive means in each zone for controlling the condition changing means to maintain predetermined conditions in each zone, timing means periodically movable to a circuit making and a circuit breaking position, means under the control of the timing means for causing each of the condition responsive means to maintain one predetermined condition as long as the timing means is in circuit making position and to causethe condition responsive means to maintain a second predetermined condition as long as the timing means is in circuit breaking position, manual means for selectively causing any of the condition responsive means to maintain one said predetermined condition at a time when it would normally be set to maintain the other predetermined condition, and means` andasse independent oi operation oi the manual means for insuring normal control of the timing means over the various condition responsive means after the timing means has moved to its other circuit controlling position.

ll. ln a condition control system, a plurality of conditionv changing means, an electrically operated regulating device for each of said condition changing means, a condition responsive control means for each oi said regulating devices, circuit connections between each o said control means and its associated regulating device and efective to permit said control means to cause said regulating device to maintain the controlled condition at a substantially constant value, means including a two position relay switch for each control means for altering said circuit connections between the control means and the regulating device to causeeither of two values of said condition to be maintained, a relay coil associated with each relay switch and effective when energized to move said relay switch from a rst position towards which it is biased to a second` position, master control means including a time switch for periodically energizing and delenergizing all of said relay coils, said time switch having a circuit making position and a circuit breaking position, circuit connections for causing all of said relay coils to be energized by said time switch only so long as the time switch is in circuit making position and to cause all of vthe 'relay coils to be deenergized by said time switchas long as the time switch is in circuit breaking position, and manually operated means associated with each relay coil for controlling the energization thereof in response to momentary closure thereof independently of the master control means.

12. .lin a condition control system, a plurality of condition changing means, an electrically operated regulating device foreach of said condition changing means, a condition responsive control means for each or said regulating devices, circuit connections between each of said control means and its associated regulating device and effective to permit said control means to cause said regulating device to maintain the controlled condition at a substantially constant value, means including a two position relay switch for each control means for altering said circuit connections between the control means and the regulating device tov cause either of two values of said condition to be maintained, a relay coil associated with each relay switch and eiective when energized'to move said relay switch from a rst position towards which it is biased to a second position, master control means including a time switch for periodically energizing and deenergizing all of said relay coils, means for controlling the energization of said relay coils, said means including second, third and fourth relay means and a timing means periodically movable to circuit making and breaking pdsitions, means for normally energizing said second relay means when the timing means is in circuit breaking position, means responsive to movement of the timing means to circuit making position for energizing the third relay means, means responsive to energization of the third relay means for energizing said relay coils, means responsive to energization of said relay coils for energizing lsaid fourth relay means, means responsive to energization of said fourth relay means for deenergizing said second and third relay means, means including said timing means for maintaining said fourth relay means energized, a maintaining circuit for said relay coils including switch means controlled by said fourth relay means, a first manual switch means associated with each relay switch for selectively opening the maintaining circuit for any of. said relay coils, and second manual switch means associated with each relay switch, and means responsive to momentary closure of any of said second manual switch means -Ior causing the energization of the associated relay coil, said means including the fourth relay when the timing means is in circuit making p0- sition and including the second relay when the timing means is in circuit breaking position.

13. In a system of the class described for controlling the condition of a plurality of spaces, condition changing means for the various spaces, condition responsive means for each of said spaces, means controlled by each condition responsive means for varying the effect of the condition changing means for that space to maintain the condition at a predetermined value, motor means associated with each of said condition responsive means for adjusting the predetermined value of the condition maintained in the space, manual switch means associated with each of said motor means controlling the energization thereof, master control apparatus for all of said motor means, said master control apparatus comprising. automatic cycling relay means and a time switch, means including said time switch and said cycling relay means for initiating the operating cycle thereof, means operated by said cycling relay means for establishing an energizing circuit for each of said motor means and then interrupting said energizing circuits, means operative upon energization of each of said motor means to establish a holding circuit therefor extending through its respective manual switch means, means including said manual switch means for deenergizing the associated motor means independently of the position of said time switch, all of said relays and motor means being deenergized in the event of power failure but said time switch operating to reinitiate, the cycle of said cycling relays upon resumption of power to reenergize said motor means.

CLARENCE W. NESSELL. 

